U.S. patent number 4,457,599 [Application Number 06/407,060] was granted by the patent office on 1984-07-03 for composite photography apparatus and method.
Invention is credited to Walter M. Sawicki.
United States Patent |
4,457,599 |
Sawicki |
July 3, 1984 |
Composite photography apparatus and method
Abstract
Apparatus and method is disclosed herein for producing a pair of
identical images on the same piece of film except for the
appearance of the background which becomes black behind one of the
images and clear behind the other. The apparatus includes a
background screen reflecting polarized light and a motion picture
camera having an image duplicating device carried before the lens
thereof comprising a beam split element for optically conducting a
pair of images simultaneously through filters via front surface
mirrors and prisms to a recording film strip. One filter is of
neutral density so that a half frame on the film strip records a
black image on a clear background while the other filter is a
polarizing filter producing a clear image on a black background on
the other half of the film strip frame.
Inventors: |
Sawicki; Walter M. (Burbank,
CA) |
Family
ID: |
23610433 |
Appl.
No.: |
06/407,060 |
Filed: |
August 11, 1982 |
Current U.S.
Class: |
352/89; 352/45;
352/46 |
Current CPC
Class: |
G03C
5/06 (20130101); G03B 15/08 (20130101) |
Current International
Class: |
G03C
5/04 (20060101); G03C 5/06 (20060101); G03B
15/08 (20060101); G03C 001/00 () |
Field of
Search: |
;352/89,45,46,47,88,81 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Hayes; Monroe H.
Attorney, Agent or Firm: Marrs; Roger A.
Claims
What is claimed is:
1. Apparatus for use in composite photography comprising the
combination of:
a motion picture camera having a lens and a length of film for
recording images thereon via said lens;
a beam splitting means carried on said camera and having optical
elements substantially lying along the optical axis of said
lens;
a background means in spaced relationship to said camera and
disposed behind a subject intended to be recorded on said film;
and
said optical elements including a beam splitting element for
optically dividing an image of said subject into a pair of
identical images and further including filter elements for
modifying said pair of images so that each image and background
therefor is reversed when recorded on said length of film.
2. The invention as defined in claim 1 wherein:
said pair of respectively reversed images are contained within a
single frame of said length of film.
3. The invention as defined in claim 2 including:
a multiplicity of front surface mirrors optically arranged between
said beam splitting element and said filters.
4. The invention as defined in claim 3 wherein:
a selected one of said filters is of neutral density so that a half
frame on said film records a black image on a clear background and
said other filter is a polarizing filter producing a clear image on
a black background on the other half of the film frame.
5. The invention as defined in claim 4 wherein:
said background means is a screen characterized as reflecting
polarized light.
6. The invention as defined in claim 5 including:
a shutter operably carried on said beam splitting means lying
across the optical axis of said camera lens.
7. The invention as defined in claim 6 including:
a first prism associated with said front surface mirrors for
receiving said image of said subject; and
a second prism disposed between each of said filters and lens for
conducting the image thereto.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of composite photography and
more particularly to a novel apparatus and method for producing a
single, composite film strip having multiple image elements derived
photographically at different times and places.
2. Brief Description of the Prior Art
Composite photography is described as the process of making
pictures in which background and foreground images are obtained
photographically from separate sources and subsequently combined to
produce a completed picture on a single film medium. To obtain a
satisfactory combination of the respective separately obtained
photographic images, means must be provided to prevent overlapping
of the respective image elements otherwise distortion and
indefiniteness would result.
The art of traveling matte photography has been in use for several
years for overcoming problems dealing with overlapping through the
use of two basic systems. The primary objective of these systems is
to produce a silhoutte of the foreground image or object in black
against a clear field which is known as a traveling matte. This
image or matte is placed in front of a background image and the two
are photographed. The traveling matte prevents the background in
the area of the foreground object from being recorded, thus leaving
a hole for the foreground to be photographed on a subsequent
exposure.
The most common system in use is commonly known as the blue screen
technique. An actor or object is positioned in front of a
translucent blue screen which is illuminated from the rear. The
actor is lit normally and both are photographed onto standard
motion picture film. Then, film undergoes a great many laboratory
duplications and filtration to eliminate the blue tint of the
screen and replace it with the background image. Inherent problems
of this system have been the danger of blue light spilling on the
actor or blue clothing, either one of which will render the actor
transparent to the background in those areas so contaminated. The
system is oftentimes costly and characterized by a cut-out look of
the foreground object since soft edges and blur are difficult to
maintain in the process.
The other system makes use of a beam splitting camera which is a
camera that can photograph the same image on two strips of film
simultaneously. Through the use of such a camera, one can produce
the foreground against black on one film and its traveling matte on
the other film. This is accomplished by the use of specially
illuminated actors and screens coupled with film stocks which are
in turn sensitive and insensitive to the particular wavelengths of
light used for photography. Sodium vapor, infra-red, ultra-violet
or similar light is used to illuminate the screen which is rendered
black on one film and clear on the other depending on the
respective films sensitivity to produce the aforementioned
photographic elements. Although this system greatly simplifies the
optical laboratory processes and produces excellent composites, its
primary disadvantage resides in the requirement for a very
specialized camera and exotic light sources. Also, the system is
subject to changing improvements in film stocks which may suddenly
become sensitive to the lights specifically designed to be
invisible to the film.
Therefore, a long standing need has existed to provide an
economical and relatively simple apparatus and method for taking
single images and combining these separate images onto a single
film medium without distortion or degradation of image quality.
SUMMARY OF THE INVENTION
Accordingly, the above problems and difficulties are obviated by
the present invention which provides for a novel apparatus and
method capable of producing a pair of identical images within a
single frame on a strip of film so that the appearance of the
background is black behind one of the images and clear behind the
other. The apparatus includes a background screen means reflecting
polarized light and a motion picture camera separated by the object
of which the picture is being taken. An image duplicating device is
carried on the camera immediately ahead of the lense which includes
a beam splitting means for redirecting the image along opposite
axes and through front surface mirror means associated with each of
the axes for redirecting the images through separate filter
networks. One of the filter networks associated with one of the
split images comprises a prism for receiving the image after
passing through a polarized filter before introduction to the film
strip frame while the other image passes through a similar prism
after passing through a neutral density filter and then to the
frame of the film strip. By this means, two identical images are
produced on the same piece of film except for the appearance of the
background screen which becomes black behind one of the split
images and clear behind the other.
Therefore, it is among the primary objects of the present invention
to provide a novel composite photography apparatus and method
wherein the matte is produced simultaneously with the foreground
image and wherein exotic lighting systems are not required.
Another object of the present invention is to provide a novel
composite photography system wherein the background images and the
foreground images are obtained from separate sources and are
subsequently combined to produce a completed picture on the same
film strip and frame without the need for expensive and complex
filming and lighting apparatus.
Still another object of the present invention is to provide a novel
polarized single film traveling matte process and apparatus
therefor which employs the use of any registered motion picture
camera coupled with a novel beam splitting means and filtering
network to record on one strip of film, a self-matting foreground
element and its traveling matte on alternate frames.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention which are believed to be
novel are set forth with particularity in the appended claims. The
present invention, both as to its organization and manner of
operation, together with further objects and advantages thereof,
may best be understood by reference to the following description,
taken in connection with the accompanying drawings in which:
FIG. 1 is a diagrammatic view of the composite photography
apparatus and method incorporating the inventive concept;
FIG. 2 is a diagrammatic view of a negative obtained from the
apparatus used in FIG. 1;
FIGS. 3 and 4 are positive prints taken from the negative shown in
FIG. 2 having the respective foregrounds and mattes combined in an
action sequence;
FIG. 5 is a diagrammatic view of a suitable background print;
FIG. 6 is a negative including the background shown in FIG. 5;
and
FIG. 7 is a print of film strip showing the final composite after
the film negative in FIG. 6 has been processed and printed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a composite photographic system is illustrated
incorporating the inventive concept which includes a conventional
motion picture camera 10 that is arranged in spaced apart
relationship with respect to a background screen 11. A subject of
interest, such as an actor or object 12, is positioned between the
camera and the screen. Mounted on the camera so as to lie along its
central optical axis, there is provided a beam splitting and
filtering apparatus which is preferrably detachably connected and
carried on the camera. The actor 12 is positioned in front of the
screen 11 so that either one reflects or transmits polarized light.
The actor is lit by conventional means such as lamp 13 and no stray
light is permitted to contaminate the screen. Only polarized light
must emanate from the screen. The image of the actor and the screen
travels to a beam splitting means 14, which includes a beam
splitting element that can be a partially silvered mirror whose
function it is to partly transmit and reflect light that falls upon
its surface. The beam splitting element 14 lies on the optical axis
of the camera lens. As can be seen in the diagram, the light
transmitted by the beam splitting element 14 is reflected by a
series of front surface mirrors 15, 16 and 17 consecutively.
Thereafter, the light is introduced through a polarized filter 18
which is positioned in such a way as to cancel out the polarized
light from the screen. The image passes through the filter 18 and
reflects from a mirror or prism 20 and is recorded through the
lense of the camera on one half of the motion picture frame. This
image consists of a normally reproduced actor in front of a black
screen as background. Conversely, the identical image of the actor
and screen is reflected by the beam splitter element 14 and
transmitted by another or second set or series of front surface
mirrors 21 and 22 to a neutral density filter 23. Filter 23 is of
neutral density so that it grays down the image of the actor and
the screen. If the polarized screen is illuminated with a greater
percentage of light than that lighting the actor, a neutral density
filter can be used to darken the actor to the point where the film
records the actor as a black silhouette while at the same time not
having enough density to effect the screen which records as white
on the film. The image passing through this latter filter reflects
on a mirror or prism 24 and records the matter on the strip of film
as the other half of the frame. It should be noted that the
distances of mirrors 21 and 22 are adjusted in relation to the rest
of the apparatus to obtain an identical length of light path of the
matte image and that of the polarized foreground image. Thereby,
identical images are produced on the film plane of the camera. In
order to insure identical images, the shutter of the camera is
removed so that it has no effect on the exposure of the film. In
its place, synchronized by any suitable means with the camera,
there is an auxilliary shutter 25 which is placed in front of the
beam splitting device or optics so that even the shutter action is
split identically. Conversely, the angle of the built-in camera
shutter can be adjusted to have a wider angle than the auxilliary
shutter. In this way, when the two shutters are put into
synchronization, the interior camera shutter will have no effect on
exposure thereby eliminating the necessity for removing it.
If desired, the process may be modified by other means so that the
beam splitting and filtering occurs behind the lense.
The following is a description of one film format and laboratory
procedure; however, any film size and method of obtaining the matte
are viable. In this description, a Vistavision motion picture
format is used. Most theatrical motion picture work makes use of a
four perforation high image on 35 mm film. Vistavision is an eight
perforation long image area that was utilized in the wide screen
processes of years ago. Since this format is essentially two full
size four perforation high images placed one on top of the other,
one can readily see that no loss of image quality is suffered by
splitting the frame in two.
FIG. 2 illustrates the negative obtained from the inventive
process. Each individual frame or separate position (if it exists)
of the foreground object is recorded on two four perforation high,
frame size images or one Vistavision frame. One image exists as a
negative actor in front of a clear screen and the identical
adjacent image is that of a clear actor in front of a black screen.
These images are separated by means such as an optical printer by
alternately printing every other image. One such skip framed print
would contain only the images composed of the silhuette actor
thereby obtaining the traveling matte shown in FIG. 4. The other
images are alternately printed in the same manner obtaining a
positive actor in front of a black background as shown in FIG.
3.
A suitable background print, such as FIG. 5 is made at any
convenient time, or may be obtained from the film library,
according to the requirements. This background image is held in
register with the traveling matte of FIG. 4 and rephotographed onto
a suitable film. This printing step yields a film having an
exposure, or latent image thereon, corresponding to the background
scene, but with an unexposed portion corresponding to the opaque
silhuette of the matte of FIG. 4. Thereafter, the same film of FIG.
6 is printed a second time with the foreground positive of FIG. 3.
The black screen surrounding the performer on this film prevents
reexposure of the background while the image of the actor fills in
the unexposed area left by the traveling matte. This operation
produces the final composite which is shown in FIG. 7 after the
film in FIG. 6 has been processed and printed.
As can be seen, a number of advantages are incurred with this
system. Any of the 35 mm motion picture formats can be used with
this process. In the case of conventional four perforation format,
some means is utilized in the printing stages of FIG. 3 and FIG. 4
to mask off those portions of the rephotographed area that are not
within a two perforation high image. If an area the size of a four
perforation frame were copied for example, some means must be
provided to prevent the adjacent images of the matte or foreground
from photographing. Most motion picture work is done in a 1.85:1
image area of a four perforation format, one can readily see that
the area of a matted actor can easily fall within the aspect ratio
above even if only two perforations of the four are used.
Furthermore, the background remains in a convenient size for
duplication being four perforations high. Any degradation that may
occur would only do so in the foreground area being matted in due
to possible enlargement of the image. Since the matte and the
foreground are produced on the same piece of film, the registration
and shrinkage characteristics of the matte are ideal. Since the
matte and foreground are shot on conventional motion picture
negative instead of high contrast film, natural blurring of the
image is preserved thereby producing a better composite without the
cut out look. Laboratory operations are greatly reduced. Polarized
light is not subject to color sensitivity so any color can be used
in the foreground object including blue. Exotic light sources such
as sodium vapor or infra-red need not be utilized.
While particular embodiments of the present invention have been
shown and described, it will be obvious to those skilled in the art
that changes and modifications may be made without departing from
this invention in its broader aspects and, therefore, the aim in
the appended claims is to cover all such changes and modifications
as fall within the true spirit and scope of this invention.
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